IBM breakthrough for making chips with nanotubes

IBM claims to have made a technological breakthrough that could allow the use of alternative materials to silicon in the production of high performance chips.

Researchers, from the company's Watson research centre, have developed a fabrication technique, which could be the key to producing industrial quantities of nanotube transistors.

The biggest problem with producing large quantities of nanotubes has previously been the inability to control their growth.

The IBM method, called constructive destruction, removes unwanted metallic nanotubes from the wafer while leaving unharmed semiconducting nanotubes. These can be used as field-effective transistors (FETs).

This process is faster than the nanotube production method used today, which involves growing the tubes one by one.

The research paper outlining the process was published in this week's Science. In the article, the IBM researchers have broken down their approach into five basic steps:

2A lithographic mask is projected onto the wafer to form electrodes (metal pads) over the nanotubes.

3These electrodes act as a switch to turn the semiconducting nanotubes on and off. Using the silicon wafer itself as an electrode, the scientists "switch-off" the semiconducting nanotubes, which essentially blocks any current from travelling through them.

4The metal nanotubes are left unprotected and an appropriate voltage is applied to the wafer, destroying only the metallic nanotubes, since the semiconducting nanotubes are now insulated.

5The result is a dense array of unharmed, working semiconducting nanotube transistors that can be used to build logic circuits.

IBM hopes to get the technology to a point where it can be used in mainstreame chip manufacturing within three years.